Characterization, classification and suitability evaluation of soils under sugarcane (Saccharum officinarum L.) cultivation at the Sugar Research Farm, University of Ilorin, Nigeria

Abstract

A reconnaissance survey conducted at the University of Ilorin Sugar Research Farm (USRF) revealed four dominant soils at Site 1 (USRF1) and one at Site 2 (USRF2). The soils were characterized and classified according to both the Soil Taxonomy (ST) and the World Reference Base for Soil Resources (WRB). Also, the suitability of the soils for sugarcane cultivation was evaluated using the limitation approach. While the USRF1 soils were reddish, the USRF2 soil was greyish due to poor drainage. The USRF1 soils were loamy sand with the AB-horizons of pedons II and III being gravelly. Pedon V had sandy loam surface, sandy clay loam subsurface and clay loam subsoil. The USRF1 soils were moderately acid while the USRF2 soil was slightly acid to slightly alkaline. Exchangeable calcium (Ca²⁺) content of the USRF2 soil which averaged 4.00 cmol_c kg^–1 was 2-3 times higher than that of the USRF1 soils. The USRF2 soil also contained higher Mg²⁺, K⁺ and Na⁺, 2-3 folds higher effective cation exchange capacity and > 10 folds higher soil organic carbon (with mean of 11.60 g kg^–1) and total nitrogen (mean of 0.94 g kg^–1). Under ST, pedons I and IV classified as Typic Haplustepts, II and III as Lithic Haplustepts and V as a Kanhaplic Haplustalf. Under WRB, pedons I and IV classified as Eutric Regosols (arenic), II and III as Endo-pisoplinthic Cambisols (arenic) and V as a Gleyic Lixisol (loamic). Pedon V was highly suitable (85.25%), I and IV moderately suitable (64.53%), II marginally suitable (47.40%) and III unsuitable (35.62%) for sugarcane cultivation.